1. Technical Field
The present invention relates to a backlight unit and a liquid crystal display having the same, and more particularly, to a backlight unit and a liquid crystal display having the same in which the disposition of a point light source is adjusted to enhance the color uniformity of the backlight unit.
2. Discussion of the Related Art
Recently, flat panel display apparatuses, such as, for example, liquid crystal displays (LCDs), plasma display panels (PDPs), and an organic light emitting diodes (OLEDs), have been developed in place of a conventional displays such as cathode ray tubes (CRTs).
An LCD comprises, for example, an LCD panel having a Thin Film Transistor (TFT) substrate, a color filter substrate, and liquid crystals disposed therebetween. As an LCD panel does not emit light by itself, the LCD may comprise a backlight unit in the rear of the TFT substrate for providing light. The transmittance of the light from the backlight unit may be adjusted according to the alignment of the liquid crystals. The LCD panel and the backlight unit may be accommodated in a chassis.
A backlight unit may be considered either an edge type or a direct type backlight unit depending upon the location of the light source of the backlight unit. The edge type backlight unit provides the light source at a lateral side of a light guiding plate and is typically used for relatively small LCDs, such as those used in laptops and desktop computers. The edge type backlight unit provides a high light uniformity with good endurance and is suitable for use in thin profile LCDs.
However, as a result of the increasing demand for larger sized LCDs, the use of direct type backlight units for LCDs has likewise increased. The direct type backlight unit provides the entire surface of the LCD with light by disposing a plurality of light sources in the rear of the LCD panel. In addition, by utilizing a plurality of light sources, the direct type backlight unit may provide a high level of brightness for an LCD as compared with the edge type backlight unit. However, the level of brightness provided by conventional direct type backlight units is generally not sufficiently uniform.
The LED, which is a point light source, has been identified as a more suitable light source for use with the direct type backlight unit, in comparison to linear light sources such as e.g., lamps. The direct type backlight unit further includes a point light source row comprising a plurality of point light source groups, wherein the point light source groups provide white color light. These point light source groups are disposed on a point light source circuit board in a line.
However, the above conventional backlight units do not provide adequate color uniformity, due to a deviation of the characteristics of the colors emitted by the point light sources of the backlight unit. As a result, a user may see horizontal strips or vertical strips when viewing the LCD.
Thus, there is a need for a backlight unit having improved color uniformity.